Microstructure failure in ferrite-martensite dual phase steel under in-situ tensile test

• Published in: Journal of iron and steel research, international Vol. 24; no. 3; pp. 350 - 356
• Main Authors: Gou, Rui-bin, Dan, Wen-jiao, Zhang, Wei-gang, Yu, Min, Zhang, Chun-yu, Qiao, Yin-hu, Ma, Lu
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01-03-2017; Springer Singapore
• Subjects: Applied and Technical Physics; Dual phase steel; Engineering; Ferrite; In-situ observation; Machines; Manufacturing; Martensite; Materials Engineering; Materials Science; Metallic Materials; Micro-fracture; Physical Chemistry; Processes; Micro-fracture; Ferrite; In-situ observation; Dual phase steel; Martensite
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1016/S1006-706X(17)30050-X

To investigate microstructure failure in ferrite-martensite dual phase steel, in-situ observations were performed on multiple plate DP800 specimens during uniaxial tensile tests. Microstructure evolution of the observed region was investigated in details. The experimental data showed that micro-cracks in various regions differed in the initiation time, and micro-failures mainly occurred from the locations with typical characteristics of stress concentration (i. e. ferrite interiors, the interfaces of ferrite-martensite grains and the martensite-martensite interfaces). Growth of micro-crack generally experienced the following stages: cracking from martensite boundaries, tiny particles in ferrite interiors, or martensite interiors, propagating in ferrite, bypassing martensite boundaries, or passing through martensite-martensite interfaces, finally ending on martensite boundaries. Martensite was one important source of micro-failure and changed the propagation of micro-cracks significantly. Microstructure deformation was inhomogeneous in the stage of plastic deformation.